TY - JOUR
T1 - Effect of essential amino acid supplementation and aerobic exercise on insulin sensitivity in healthy older adults
T2 - A randomized clinical trial
AU - Randolph, Amanda C.
AU - Markofski, Melissa M.
AU - Rasmussen, Blake B.
AU - Volpi, Elena
N1 - Funding Information:
M.M.M. collected and analyzed samples. A.C.R. analyzed samples, performed statistical analysis, and wrote the manuscript. E.V. and B.B.R. conceived the study. E.V. supervised the study. All authors contributed to the discussion, in addition to critically reviewing and editing the manuscript. E.V. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. This work was supported by the National Institutes of Health ( R01 AG030070 ; R01 AG030070S1 ; P30 AG024832 , UL1 TR001439 ; T32 AG051131 ; and F30 AG058381 ). Amino acid supplements were donated by Ajinomoto, Inc. Preliminary data were previously presented at the Gerontological Society of America Annual Scientific Meeting in 2015, and the resulting abstract was published in The Gerontologist .
Publisher Copyright:
© 2019 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism
PY - 2020/5
Y1 - 2020/5
N2 - Background & aims: The combination of prolonged essential amino acid (EAA) supplementation and aerobic exercise training (Ex) improves muscle protein metabolism, strength and function in healthy older adults. However, excess EAA intake may worsen insulin sensitivity. Here we report the effects of EAA supplementation (EAA, n = 11), placebo (PLA, n = 10), aerobic exercise with placebo (Ex + PLA, n = 11) or Ex with EAA supplementation (Ex + EAA, n = 10) for 22 weeks on insulin sensitivity in non-diabetic older adults. Methods: A 2 × 2 design with block randomization and double blinding for supplement or placebo was used. Subjects ingested EAA (15 g) or placebo daily. Exercising subjects participated in supervised progressive vigorous treadmill walking 3 times weekly. Measures of insulin sensitivity by oral glucose tolerance testing were collected at baseline and 22 weeks. Dietary intakes of protein and specific amino acids were determined in a subset of subjects. Results: Overall, exercise improved insulin sensitivity, while EAA supplementation had no effect. In the dietary subset, post-intervention insulin sensitivity did not correlate significantly with the total intake of EAA, anti-angiogenic amino acids (cysteine, methionine), or branched-chain amino acids (isoleucine, leucine, valine). Conclusions: Overall, we conclude that in healthy older adults with moderate protein intake, EAA supplementation is metabolically safe as it does not decrease insulin sensitivity regardless of its combination with aerobic exercise. Thus, daily protein intake should be controlled for when modeling insulin sensitivity. Future studies should explore the role of increased blood flow as a potential explanatory factor for the observed interaction between aerobic exercise and supplementation. Clinical trial registration number: NCT00872911.
AB - Background & aims: The combination of prolonged essential amino acid (EAA) supplementation and aerobic exercise training (Ex) improves muscle protein metabolism, strength and function in healthy older adults. However, excess EAA intake may worsen insulin sensitivity. Here we report the effects of EAA supplementation (EAA, n = 11), placebo (PLA, n = 10), aerobic exercise with placebo (Ex + PLA, n = 11) or Ex with EAA supplementation (Ex + EAA, n = 10) for 22 weeks on insulin sensitivity in non-diabetic older adults. Methods: A 2 × 2 design with block randomization and double blinding for supplement or placebo was used. Subjects ingested EAA (15 g) or placebo daily. Exercising subjects participated in supervised progressive vigorous treadmill walking 3 times weekly. Measures of insulin sensitivity by oral glucose tolerance testing were collected at baseline and 22 weeks. Dietary intakes of protein and specific amino acids were determined in a subset of subjects. Results: Overall, exercise improved insulin sensitivity, while EAA supplementation had no effect. In the dietary subset, post-intervention insulin sensitivity did not correlate significantly with the total intake of EAA, anti-angiogenic amino acids (cysteine, methionine), or branched-chain amino acids (isoleucine, leucine, valine). Conclusions: Overall, we conclude that in healthy older adults with moderate protein intake, EAA supplementation is metabolically safe as it does not decrease insulin sensitivity regardless of its combination with aerobic exercise. Thus, daily protein intake should be controlled for when modeling insulin sensitivity. Future studies should explore the role of increased blood flow as a potential explanatory factor for the observed interaction between aerobic exercise and supplementation. Clinical trial registration number: NCT00872911.
KW - Glucose metabolism
KW - Matsuda index
KW - Sarcopenia
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U2 - 10.1016/j.clnu.2019.06.017
DO - 10.1016/j.clnu.2019.06.017
M3 - Article
C2 - 31307843
AN - SCOPUS:85068806488
SN - 0261-5614
VL - 39
SP - 1371
EP - 1378
JO - Clinical Nutrition
JF - Clinical Nutrition
IS - 5
ER -